OJITO AMPHITHEATER: COMBINING HIGH-RESOLUTION DIGITAL IMAGERY AND TERRESTRIAL LIDAR FOR IMPROVED UNDERSTANDING OF SUBSURFACE FLUID FLOW IN THE MORRISON FORMATION

For the past two decades, subsurface heterogeneity studies have focused on modeling sedimentary structure and facies distributions using a variety of geostatistical approaches; however, due to limitations in parameterization data these approaches may not capture realistic facies geometries and subsequent fluid flow paths. Vertical variability is often observed at high resolution, as in core and geophysical well logs, however lateral heterogeneity is difficult to capture and as a result, a high amount of uncertainty exists in subsurface flow models. In an attempt to more accurately characterize aquifer sediments, an outcrop analog-based approach utilizing terrestrial lidar and high-resolution digital photography is combined with lithofacies analysis.

In the summer of 2011, terrestrial lidar scans and high resolution digital images of approximately 15,000 m² of contiguous cliff face were acquired of a Westwater Canyon Member, Morrison Formation outcrop in Ojito Wilderness, New Mexico, USA. The resulting 3D lidar point cloud, ~ 400 points/m², was used to develop a mesh with ~ 2.5 cm resolution. Architectural element analysis of the outcrop showed correlation of the major bounding surfaces, i.e. 5^th order, across the study area. These surfaces are used to define individual depositional and modeling units. The digital images will be processed through a series of photogrammetric techniques including edge detection and textural filters to delineate different facies and sedimentary structures. The resulting classified digital images will be projected onto the high-resolution mesh to create a highly realistic digital outcrop model for parameterization of an aquifer model.